1. Field of the Invention
Exemplary embodiments of the present invention relate to a method for preparing pellets from rice husk and an apparatus for removing odor using rice husk pellet bio-media; and, more particularly, to a method for preparing cylindrical rice husk pellets, including grinding rice husk, a by-product of rice milling, and extruding the ground rice husk with a binder through an extruder at high temperature, and to an apparatus for removing atmospheric odor using the prepared rice husk pellets as bio-media.
2. Description of Related Art
In biological deodorization methods which have recently attracted attention, materials for media on which microorganisms grow include ceramics, wood barks, porous polymer media, etc. However, the existing media have problems in that water and nutrients essential for the growth of microorganisms should be supplied in order for each medium to be used as a bio-medium and also that a decrease in pH of water caused by the oxidation of odor-causing compounds leads to the death of microorganisms.
In an attempt to solve the problems associated with the existing bio-media, Korean Patent Registration No. 0375163 discloses a biological deodorization method employing rice husk and rice-straw and an apparatus for carrying out the method. According to the disclosure of the Korean Patent, the problem that the pH of spray water decreases is overcome by using rice husk as media for providing a carbon source to microorganisms and oxidizing odor-causing compounds and by using rice-straw as microbial media carrier for reducing oxidized odor compounds. Also, micronutrients released from each of the media act as nutrients essential for the growth of microorganisms to eliminate the need to supply external carbon sources and nutrients.
However, in the above Korean Patent, the particle size of rice husk, a by-product of rice milling, is as small as about 0.5 cm or smaller, a water film is formed in pores between rice husk particles after water spray, and as the operating time becomes longer, the rice husk layer settles under load to reduce the porosity of the rice husk layer. For these reasons, there is a problem in that, when odor-containing air is introduced, a great pressure loss and channeling occur. In addition, there is a problem in that the structure of the apparatus is complex, because, in order to prevent the pH of circulating spray water from decreasing, rice-straw and rice husk are placed separately in a water bath for reduction and a water bath for oxidation, respectively, such that the water baths are operated separately.